Denver: A campaign is underway to ask Denver voters about allowing marijuana consumption in bars and other places that only allow people over 21.

Partygoers listen to music and smoke marijuana during the annual 4/20 marijuana festival in Denver’s downtown Civic Centre Park in April this year. Pic/AP

Activists who campaigned for recreational pot legalisation in Colorado have launched a petition drive to allow what they call “limited social marijuana consumption” at bars. The activists need about 5,000 signatures to get the question on November ballots.

It would allow bars or clubs to allow marijuana use as long as patrons bring their own weed and comply with clean-air laws and consumed on an outside patio. “Marijuana’s now a legal product for adults in Denver, and it’s really time that we give adults a place to use it legally and socially,” said Mason Tvert, who ran Colorado’s 2012 campaign to legalise recreational pot.

Colorado law prohibits recreational pot consumption “openly and publicly or in a manner that endangers others.” It does not, however, bar against consumption in private over-21 clubs. The Denver petition comes after that City Council rejected pot-friendly bars.

Denver has several underground clubs where patrons use marijuana for a joining fee, but the city has intermittently arrested people for public consumption at those clubs. Among the supporters is Jane West, an events promoter who last year arranged a Classically Cannabis concert with the Colorado Symphony Orchestra.

The city threatened to block the concert, citing public consumption laws. The Symphony rebranded the concerts as private bring-your-own-cannabis fundraisers, and the city dropped its objections. West became one of the first to sign the Denver petition. The petitions are due by early August.